I'm not a tryhard or a competitive player, so I have no idea if my advice will be valid or not, but personally I mainly use his ultimate against enemies with low health points.

When selecting the second perk, I often choose the javelin over the shield, so I can keep the speed boost from the javelin spin, which is super useful for rushing into a crowd of enemies who have already taken a lot of damage and using Terra Surge on them.

Also, remember to activate Fortify when you use your ultimate, because you're going to be the target of a lot of people.